This invention relates to control levers for powered machines, such as vehicles, and particularly to reducing vibration energy transmitted through such control levers.
Control levers are often used to control the operation and movement of different vehicles, such as watercraft, aircraft (e.g., airplanes and helicopters), and ground vehicles (e.g., automobiles, trucks, and motorcycles). Most control levers have knobs connected to their ends.
Operating a vehicle produces vibrations. Vibrations are produced by vehicle engines (e.g., the jet engine of an airplane, the gasoline engine of a car, the diesel engine of a semi-truck), other moving parts of the vehicle (e.g., a drive train), or may be produced as a result of vehicle travel (e.g., waves hitting a boat). Sources of vibration in ground vehicles include vibrations transmitted from tires traveling over the ground or a roadway, and operation of the engine or various other components (e.g., a vehicle transmission).
In vehicles, noise and vibrations may be transmitted from different parts of the vehicle, through the walls of an operator""s compartment via control levers, and into the interior of the operator""s compartment. For example, in a truck, vibrations from the vehicle""s transmission can be transmitted through a gear shift lever and into the truck cab. Such vibrations may be caused by the transmission itself or may be produced in other parts of the vehicle (e.g., by the vehicle engine or other parts of the drive train, by tires travelling along a rough road, etc.) and transmitted through the transmission. Problems created by transmission noise and vibration are especially common in larger ground vehicles (e.g., dump trucks, semi-trucks), since most such vehicles are equipped with a lever which is manually operated to cause shifting of the transmission.
Certain types of mechanisms for dampening noise and vibrations transmitted through gear shift levers are known. Examples are set forth in U.S. Pat. Nos. 5,579,661; 3,800,909 and 5,467,664. However, a need nevertheless exists for an improved vibration isolator for use in lever assemblies.
A vibration-dampening control lever assembly in one form comprises a knob, an elastomeric isolator coupled to the knob, and a lever coupled to the elastomeric isolator. The assembly may also comprise a lever-receiving insert, one or more internal passageways which bypass the elastomeric isolator, and a detachable hollow skirt. In some forms, the elastomeric isolator is captured and compressed by an isolator receiver.
The knob may define an internal isolator-receiving cavity in the base of the knob which is sized to receive the elastomeric isolator. In such embodiments, the isolator can be mounted directly or indirectly to engage an inside wall of the cavity.
The elastomeric isolator may be a one-piece homogeneous monolithic annular ring of elastomeric material, such as rubber. Alternatively, the elastomeric isolator may be of multi-piece construction, such as comprising two or more isolator fragments.
The lever is typically generally elongated and may comprise a type of control lever for operating or controlling a function of the vehicle, such as the shifting of a transmission. The lever and knob are independently coupled to the elastomeric isolator. Thus, the isolator acts as an intermediary between the lever and the knob and reduces vibrations transmitted from the lever to the knob.
In a specific embodiment, the lever is coupled to a lever-receiving insert, and this insert is coupled to the elastomeric isolator. The insert may include a flange. In a suitable example, the isolator may be positioned within the isolator-receiving cavity of the knob with the insert flange positioned between the elastomeric isolator and the upper wall of the knob defined cavity. In such an embodiment, the flange can be sized to provide resistance to pivoting motion of the knob.
In some embodiments, the knob defines one or more internal passageways which bypass the isolator. These passageways can provide conduits for signal carriers (such as electrical wires or pneumatic lines). These control signal carriers may connect a switch or other control means mounted on the knob to vehicle operating mechanism, such as the transmission of the vehicle.
The assembly may include a hollow skirt detachably mounted to or otherwise coupled to the knob and enclosing a portion of the lever. The skirt may be rigid or flexible, depending on the needs of the vehicle user. The skirt may have a shelf for providing additional support from below to the elastomeric isolator located within the knob cavity.
The elastomeric isolator may be engaged by an isolator receiver with the isolator and receiver being positioned in the knob cavity. The isolator receiver may be annular with upper and lower flanges sized to capture and compress the elastomeric isolator. The receiver may engage an interior wall of the knob cavity.
The present invention is directed toward new and non-obvious aspects of a lever and shift knob isolator alone and in various combinations and sub-combinations thereof and as set forth in the claims below.